If Hong Kong is to tackle bad air seriously, it needs policies to specifically deal with roadside pollution. Photo: Sam Tsang

A government study has shown that the city achieved its overall clean-air targets in 2010, cutting emission levels of four pollutants by up to 60 per cent compared with 1997. But this ignores the real problem - roadside air pollution - which just keeps getting worse.

Since the study was released, Chief Executive Leung Chun-ying has named the environment as one of the deep-rooted problems he will address with an interventionist approach to governing, such as phasing out old diesel-run vehicles. And environment secretary Wong Kam-sing has said the government will consider tough measures, such as not renewing licences for diesel commercial vehicles more than 15 years old, which are among the chief roadside-pollution culprits.

We trust this is a taste of things to come. Road transport accounted for 286,000 tonnes of sulphur dioxide pollution in 2010, up 15,000 tonnes in one year alone. When other countries are preparing to introduce Euro VI emission standards starting next year, Hong Kong still has 60,000 Euro I and II emission standard vehicles of 12 to 18 years old on its roads.

Wong said what air-quality experts have been saying for years - that if Hong Kong is to tackle bad air seriously, it needs policies to specifically deal with roadside pollution.

That said, the operators of polluting diesel vehicles are not breaking current transport and environmental rules, since their vehicles are licensed under them. One operator has warned, reasonably enough, that some will be prepared to take legal action to defend their right to continue to earn their livelihoods.

Clearly, there will need to be effective incentives for drivers to upgrade willingly to acceptable standards. Existing subsidies have proven to be inadequate in value and coverage of the city's 120,000 diesel vehicles.

The government is right to be prudent with such handouts. But in this case it can be confident that the public would see cleaner roadside air - the stuff that we breathe - as good value for a lot of money.

This article appeared in the South China Morning Post print edition as Cleaner air is never too dear

Be prepared for a shock. Even when Transport Department has forced all the "dirty old diesel engined buses and lorries" off the roads, Hong Kong will discover there is barely any improvement in road-side pollution levels.There will be no substantial improvement until you also get most of the 450,000 cars and thousands of small vans off our down-town streets. These vehicles are not even inspected for faulty exhausts and emission standards. This is another aspect of Hong Kong's obscene 'wealth gap'. It is mainly the car-owners who point fingers at and blame "dirty buses" because they get in their way when driving.Wealthy car owners are permitted to occupy much of our road space and travel in comfort while the masses are forced to stand squashed in sardine tins and walk miles in underground tunnels to cross streets. At the same time these car owners are also permitted to poison us all with their poorly maintained car emissions systems. A curse on Henry Ford!